(a) Field of the Invention
The present invention relates to a housing structure for an airbag.
(b) Description of the Related Art
Generally, in order to protect an occupant during a vehicle crash, an airbag module is installed in the steering wheel or in the instrument panel.
The airbag module deploys an airbag when a vehicle crashes, thus preventing an occupant from colliding with the windshield and reducing injuries on the occupant.
The airbag module includes an airbag housing cover, an inflator which generates gas when a vehicle crashes, an airbag which is deployed by gas generated by the inflator, a sensor, and an electronic control module which ignites a percussion cap of the inflator.
The inflator includes a percussion cap which is ignited by a control signal output from the electronic control module, and generates gas compositions in response to the ignition of the percussion cap.
In such an airbag module, if a crash sensor monitors a speed decrease caused by a frontal collision, the crash sensor generates a predetermined signal. If the electronic control module receives the collision signal output from the crash sensor, the electronic control module ignites the percussion cap of the inflator which burns gas generating compositions.
The gas generated by the inflator rapidly inflates and deploys the airbag which protects an occupant from moving toward. At the same time, gas is discharged from the airbag through a gas discharging hole perforated in the airbag which absorbs the impact from the occupant, thereby reducing injuries on an occupant.
FIG. 1 is a drawing showing a pressure gradient of gas generated in a conventional inflator.
Referring to FIG. 1, when an airbag (not shown) is deployed, gas pressure changes with a gradient A of FIG. 1.
A top pressure in the gradient A is a pressure at which a general airbag operates. The pressure range at which a general airbag operates is between about 450 KPa to about 550 KPa. However, this amount of pressure may inflict severe injuries on a head, a neck, and a chest of an occupant in case the occupant does not fasten a seat belt or the occupant is sitting at the front portion of the seat.
On the other hand, if the pressure of an inflator deploying an airbag is substantially decreased or if the size of an airbag is decreased, an inflated airbag cannot sufficiently absorb the impact with the occupant, resulting in injury to the occupant.
In FIG. 1, gradient B is a pressure change at which injuries on a occupant can be minimized with the top pressure in gradient B being between about 340 KPa to about 380 KPa. Recently, technology for deploying an airbag with a pressure at which injuries on an occupant can be minimized will be explained in detail in this invention.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.